// Copyright (C) 2024 Kumo inc.
// Author: Jeff.li lijippy@163.com
// All rights reserved.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
//
#pragma once
//
// Deal with the differences between Microsoft and GNU implemenations
// of hash_map. Allows all platforms to use |turbo::hash_map| and
// |turbo::hash_set|.
//  eg:
//   turbo::hash_map<int, std::string> my_map;
//   turbo::hash_set<int> my_set;
//
// NOTE: It is an explicit non-goal of this class to provide a generic hash
// function for pointers.  If you want to hash a pointers to a particular class,
// please define the template specialization elsewhere (for example, in its
// header file) and keep it specific to just pointers to that class.  This is
// because identity hashes are not desirable for all types that might show up
// in containers as pointers.


#include <utility>
#include <limits>
#include <turbo/base/macros.h>
#include <turbo/hash/m3.h>   // fmix64

#if defined(COMPILER_MSVC)
#include <hash_map>
#include <hash_set>

#define TURBO_HASH_NAMESPACE stdext

#elif defined(COMPILER_GCC)
#if defined(OS_ANDROID)
#define TURBO_HASH_NAMESPACE std
#else
#define TURBO_HASH_NAMESPACE __gnu_cxx
#endif

// This is a hack to disable the gcc 4.4 warning about hash_map and hash_set
// being deprecated.  We can get rid of this when we upgrade to VS2008 and we
// can use <tr1/unordered_map> and <tr1/unordered_set>.
#ifdef __DEPRECATED
#define CHROME_OLD__DEPRECATED __DEPRECATED
#undef __DEPRECATED
#endif

#if defined(OS_ANDROID)
#include <hash_map>
#include <hash_set>
#else

#include <ext/hash_map>
#include <ext/hash_set>

#endif

#include <string>

#ifdef CHROME_OLD__DEPRECATED
#define __DEPRECATED CHROME_OLD__DEPRECATED
#undef CHROME_OLD__DEPRECATED
#endif

namespace TURBO_HASH_NAMESPACE {

#if !defined(OS_ANDROID)
// The GNU C++ library provides identity hash functions for many integral types,
// but not for |long long|.  This hash function will truncate if |size_t| is
// narrower than |long long|.  This is probably good enough for what we will
// use it for.

#define TURBO_DEFINE_TRIVIAL_HASH(integral_type) \
    template<> \
    struct hash<integral_type> { \
      std::size_t operator()(integral_type value) const { \
        return static_cast<std::size_t>(value); \
      } \
    }

    TURBO_DEFINE_TRIVIAL_HASH(long long);

    TURBO_DEFINE_TRIVIAL_HASH(unsigned long long);

#undef TURBO_DEFINE_TRIVIAL_HASH
#endif  // !defined(OS_ANDROID)

// Implement string hash functions so that strings of various flavors can
// be used as keys in STL maps and sets.  The hash algorithm comes from the
// GNU C++ library, in <tr1/functional>.  It is duplicated here because GCC
// versions prior to 4.3.2 are unable to compile <tr1/functional> when RTTI
// is disabled, as it is in our build.

#define DEFINE_STRING_HASH(string_type) \
    template<> \
    struct hash<string_type> { \
      std::size_t operator()(const string_type& s) const { \
        std::size_t result = 0; \
        for (string_type::const_iterator i = s.begin(); i != s.end(); ++i) \
          result = (result * 131) + *i; \
        return result; \
      } \
    }

    DEFINE_STRING_HASH(std::string);

#undef DEFINE_STRING_HASH

}  // namespace TURBO_HASH_NAMESPACE

#else  // COMPILER
#error define TURBO_HASH_NAMESPACE for your compiler
#endif  // COMPILER

namespace turbo {
    using TURBO_HASH_NAMESPACE::hash_map;
    using TURBO_HASH_NAMESPACE::hash_multimap;
    using TURBO_HASH_NAMESPACE::hash_multiset;
    using TURBO_HASH_NAMESPACE::hash_set;

// Implement hashing for pairs of at-most 32 bit integer values.
    inline std::size_t HashInts32(uint32_t value1, uint32_t value2) {
        uint64_t value1_64 = value1;
        uint64_t hash64 = (value1_64 << 32) | value2;
        return static_cast<size_t>(turbo::fmix64(hash64));
    }

// Implement hashing for pairs of up-to 64-bit integer values.
// We use the compound integer hash method to produce a 64-bit hash code, by
// breaking the two 64-bit inputs into 4 32-bit values:
// http://opendatastructures.org/versions/edition-0.1d/ods-java/node33.html#SECTION00832000000000000000
// Then we reduce our result to 32 bits if required, similar to above.
    inline std::size_t HashInts64(uint64_t value1, uint64_t value2) {
        uint32_t short_random1 = 842304669U;
        uint32_t short_random2 = 619063811U;
        uint32_t short_random3 = 937041849U;
        uint32_t short_random4 = 3309708029U;

        uint32_t value1a = static_cast<uint32_t>(value1 & 0xffffffff);
        uint32_t value1b = static_cast<uint32_t>((value1 >> 32) & 0xffffffff);
        uint32_t value2a = static_cast<uint32_t>(value2 & 0xffffffff);
        uint32_t value2b = static_cast<uint32_t>((value2 >> 32) & 0xffffffff);

        uint64_t product1 = static_cast<uint64_t>(value1a) * short_random1;
        uint64_t product2 = static_cast<uint64_t>(value1b) * short_random2;
        uint64_t product3 = static_cast<uint64_t>(value2a) * short_random3;
        uint64_t product4 = static_cast<uint64_t>(value2b) * short_random4;

        uint64_t hash64 = product1 + product2 + product3 + product4;

        if (sizeof(std::size_t) >= sizeof(uint64_t))
            return static_cast<std::size_t>(hash64);

        uint64_t odd_random = 1578233944LL << 32 | 194370989LL;
        uint32_t shift_random = 20591U << 16;

        hash64 = hash64 * odd_random + shift_random;
        std::size_t high_bits = static_cast<std::size_t>(
                hash64 >> (8 * (sizeof(uint64_t) - sizeof(std::size_t))));
        return high_bits;
    }

#define TURBO_DEFINE_32BIT_PAIR_HASH(Type1, Type2) \
inline std::size_t HashPair(Type1 value1, Type2 value2) { \
  return HashInts32(value1, value2); \
}

    TURBO_DEFINE_32BIT_PAIR_HASH(int16_t, int16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int16_t, uint16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int16_t, int32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int16_t, uint32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint16_t, int16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint16_t, uint16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint16_t, int32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint16_t, uint32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int32_t, int16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int32_t, uint16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int32_t, int32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(int32_t, uint32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint32_t, int16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint32_t, uint16_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint32_t, int32_t);

    TURBO_DEFINE_32BIT_PAIR_HASH(uint32_t, uint32_t);

#undef TURBO_DEFINE_32BIT_PAIR_HASH

#define TURBO_DEFINE_64BIT_PAIR_HASH(Type1, Type2) \
inline std::size_t HashPair(Type1 value1, Type2 value2) { \
  return HashInts64(value1, value2); \
}

    TURBO_DEFINE_64BIT_PAIR_HASH(int16_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int16_t, uint64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint16_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint16_t, uint64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int32_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int32_t, uint64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint32_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint32_t, uint64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, int16_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, uint16_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, int32_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, uint32_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(int64_t, uint64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, int16_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, uint16_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, int32_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, uint32_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, int64_t);

    TURBO_DEFINE_64BIT_PAIR_HASH(uint64_t, uint64_t);

#undef TURBO_DEFINE_64BIT_PAIR_HASH
}  // namespace turbo

namespace TURBO_HASH_NAMESPACE {

// Implement methods for hashing a pair of integers, so they can be used as
// keys in STL containers.

// containers by default

#if defined(COMPILER_MSVC)

    template<typename Type1, typename Type2>
    inline std::size_t hash_value(const std::pair<Type1, Type2>& value) {
      return turbo::HashPair(value.first, value.second);
    }
    template<typename Type>
    inline std::size_t hash_value(Type* ptr) {
      return (uintptr_t)ptr;
    }

#elif defined(COMPILER_GCC)

    template<typename Type1, typename Type2>
    struct hash<std::pair<Type1, Type2> > {
        std::size_t operator()(std::pair<Type1, Type2> value) const {
            return turbo::HashPair(value.first, value.second);
        }
    };

    template<typename Type>
    struct hash<Type *> {
        std::size_t operator()(Type *ptr) const {
            return (uintptr_t) ptr;
        }
    };

#else
#error define hash<std::pair<Type1, Type2> > for your compiler
#endif  // COMPILER

}

#undef TURBO_DEFINE_PAIR_HASH_FUNCTION_START
#undef TURBO_DEFINE_PAIR_HASH_FUNCTION_END
